Synopsis

Description

The hawq ssh utility allows you to run bash shell commands on multiple hosts at once using SSH (secure shell). You can execute a single command by specifying it on the command-line, or omit the command to enter into an interactive command-line session.

To specify the hosts involved in the SSH session, use the -f option to specify a file containing a list of host names, or use the -h option to name single host names on the command-line. At least one host name (-h) or a host file (-f) is required. Note that the current host is not included in the session by default — to include the local host, you must explicitly declare it in the list of hosts involved in the session.

Before using hawq ssh, you must have a trusted host setup between the hosts involved in the SSH session. You can use the utility hawq ssh-exkeys to update the known host files and exchange public keys between hosts if you have not done so already.

If you do not specify a command on the command-line, hawq ssh will go into interactive mode. At the hawq ssh command prompt (=>), you can enter a command as you would in a regular bash terminal command-line, and the command will be executed on all hosts involved in the session. To end an interactive session, press CTRL+D on the keyboard or type exit or quit.

If a user name is not specified in the host file or via the -u option, hawq ssh will execute commands as the currently logged in user. To determine the currently logged in user, do a whoami command. By default, hawq ssh goes to $HOME of the session user on the remote hosts after login. To ensure commands are executed correctly on all remote hosts, you should always enter absolute paths.

Arguments

-f <hostfile_hawqssh>

Specifies the name of a file that contains a list of hosts that will participate in this SSH session. The host name is required, and you can optionally specify an alternate user name and/or SSH port number per host. The syntax of the host file is one host per line as follows:

[username@]hostname[:ssh_port]

-h <hostname>

Specifies a single host name that will participate in this SSH session. You can use the -h option multiple times to specify multiple host names.

Options

<bash_command>

A bash shell command to execute on all hosts involved in this session (optionally enclosed in quotes). If not specified, hawq ssh will start an interactive session.

-e (echo)

Optional. Echoes the commands passed to each host and their resulting output while running in non-interactive mode.

-u <username>

Specifies the userid for the SSH session.

-v (verbose mode)

Reports additional messages in addition to the command output when running in non-interactive mode.

--version

Displays the version of this utility.

-?, --help

Displays the online help.

Examples

Start an interactive group SSH session with all hosts listed in the file hostfile_hawqssh:

$ hawq ssh -f hostfile_hawqssh

At the hawq ssh interactive command prompt, run a shell command on all the hosts involved in this session.

=> ls -a /data/path-to-masterdd/*

Exit an interactive session:

=> exit
=> quit

Start a non-interactive group SSH session with the hosts named sdw1 and sdw2 and pass a file containing several commands named command_file to hawq ssh:

$ hawq ssh -h sdw1 -h sdw2 -v -e < command_file

Execute single commands in non-interactive mode on hosts sdw2 and localhost: